The present invention relates to a hot-rolled steel sheet for a non-oriented
electrical steel sheet, a non-oriented electrical steel sheet, and a manufacturing method
thereof.
Priority is claimed on Japanese Patent Application No. 2020-027000, filed in
Japan on February 20, 2020, the content of which is incorporated herein by reference.
[Related Art]
[0002]
In recent years, due to the globally intensifying demand for energy saving in
electrical equipment, for non-oriented electrical steel sheets that are used as iron core
materials for rotating machinery as well, there has been a demand for higher
performance characteristics. Specifically, among motors in electrical products, for socalled
high-efficiency equipment, high-grade materials having an intrinsic resistance,
which is increased by increasing the Si and Al contents, and increased grain sizes have
been being used. However, these methods increase the manufacturing costs of nonoriented
electrical steel sheets. Therefore, from the viewpoint of cost reduction, it is
important to simplify the manufacturing steps.
[0003]
Self-annealing in hot rolling is a technique by which the skipping of hot-rolled
sheet annealing can be expected. The purpose of hot-rolled sheet annealing is the
- 1 -
recrystallization of hot-rolled steel sheets (hot-rolled sheets) and the acceleration of
grain growth, and this makes it possible to eliminate a problem of a shape defect called
rigging and to improve magnetic characteristics. A technique by which this effect is
obtained by so-called self-annealing, in which a hot-rolled steel sheet is annealed at a
temperature of a hot-rolled coil itself, will be disclosed as follows.
[0004]
For example, Patent Document 1 discloses a self-annealing technique in which,
for a non-oriented electrical steel sheet containing, by mass%, C: :::; 0.005%, Si: 0.1% to
2.0%, Mn: 0.05% to 0.6%, and Al: :::; 0.5%, having a specified number density of AlN
having an average diameter of 10 to 200 nm, and having a favorable magnetic flux
density, the coiling temperature of hot rolling is set to 780°C or higher.
[0005]
Patent Document 2 discloses a technique for skipping hot-rolled sheet
annealing, in which a hot-rolled sheet contains, by mass%, C: :::; 0.008%, 2% :::; Si + Al :::;
3%, and 0.02 :::; Mn:::; 1.0% and satisfies a relationship of 0.3% :::; Al/(Si + Al) :::; 0.5%,
the hot-rolled finish rolling temperature is set to 1 050°C or higher, the subsequent nonwater
injection time is set to 1 second or longer and 7 seconds or shorter, and the hotrolled
sheet is coiled at 700°C or lower by water injection cooling.
[0006]
Patent Document 3 discloses a method in which a hot-rolled steel sheet
contains, by weight%, C: 0.010% or less, Si: 0.1% or more and 2.0% or less, Mn: 0.1%
or more and 1.5% or less, Al: 0.1% or more and 1.0% or less, Sn: 0.02% or more and
0.20% or less, and Cu: 0.1% or more and 1.0% or less, hot-rolled sheet annealing or
self-annealing is carried out at a temperature of the Ac 1 transformation point or lower,
and a non-oriented electrical steel sheet having a high magnetic flux density and a low
- 2 -
iron loss is manufactured.
[0007]
These methods accelerate grain growth in hot-rolled steel sheets and improve
magnetic characteristics while skipping hot-rolled sheet annealing. However, in these
methods, there has been created a new problem of an increase in the amount of scale
formed on hot-rolled steel sheets, which makes the pickling property poor, decreases the
pickling efficiency, or degrades the surface quality of product sheets. Therefore, these
methods have a problem in that no merit comparable to the skipping of hot-rolled sheet
annealing can be obtained.
[Prior Art Document]
[Patent Document]
[0008]
[Patent Document 1] PCT International Publication No. WO 2013/069754
[Patent Document 2] Japanese Unexamined Patent Application, First
Publication No. 2010-242186
[Patent Document 3] Japanese Unexamined Patent Application, First
Publication No. H4-6220
[Disclosure of the Invention]
[Problems to be Solved by the Invention]
[0009]
The present invention has been made in view of such a problem and provides a
hot-rolled steel sheet for a non-oriented electrical steel sheet which reduces a scale
residue during pickling and makes the surface quality of product sheets favorable, a
manufacturing method thereof, a non-oriented electrical steel sheet, and a
manufacturing method thereof.
- 3 -
[Means for Solving the Problem]
[0010]
The gist of the present invention is as described below.
(1) A hot-rolled steel sheet for a non-oriented electrical steel sheet according to
one aspect of the present invention contains, by mass%, C: 0.0050% or less, Si: 0.5% or
more and 3.5% or less, Mn: 0.1% or more and 1.5% or less, Al: 0.1% or more and 1.5%
or less, Cu: 0.01% or more and 0.10% or less, Sn: 0.01% or more and 0.20% or less,
and a remainder including Fe and impurities, in which the hot-rolled steel sheet has a
Cu concentration peak value of 0.12% or more in a range from a surface theereof to a
depth of 10 !-liD.
(2) A non-oriented electrical steel sheet according to another aspect of the
present invention contains, by mass%, C: 0.0050% or less, Si: 0.5% or more and 3.5%
or less, Mn: 0.1% or more and 1.5% or less, Al: 0.1% or more and 1.5% or less, Cu:
0.01% or more and 0.10% or less, Sn: 0.01% or more and 0.20% or less, and a
remainder including Fe and impurities, in which the non-oriented electrical steel sheet
has a Cu concentration peak value of 0.12% or more in a range from a surface thereof to
a depth of 5 !-liD.
(3) A manufacturing method of a hot-rolled steel sheet for a non-oriented
electrical steel sheet according to another aspect of the present invention is a
manufacturing method of the hot-rolled steel sheet for a non-oriented electrical steel
sheet according to the (1) including steelmaking and hot rolling, in which the hot rolling
includes slab heating, rough rolling, finish rolling, and coiling, an air ratio in the slab
heating of the hot rolling is set to 1.0 or more and 1.2 or less, a temperature of a roughrolled
steel sheet immediate! y before the finish rolling of the hot rolling is set to 1 ooooc
or higher and 1 050°C or lower, a finish rolling temperature in the finish rolling of the
- 4 -
hot rolling is set to 930°C or higher and 970°C or lower, and a coiling temperature in
the coiling of the hot rolling is set to 750°C or higher and 800°C or lower.
( 4) A manufacturing method of a non -oriented electrical steel sheet according
to another aspect of the present invention is a manufacturing method of the non-oriented
electrical steel sheet according to the (2) including pickling, cold rolling, and final
annealing, in which, in the cold rolling, the hot-rolled steel sheet for a non-oriented
electrical steel sheet according to the (1) is cold-rolled.
(5) The manufacturing method of a non-oriented electrical steel sheet
according to the ( 4 ), in which a pickling solution used in the pickling may contain
thiosulfate.
[Effects of the Invention]
[0011]
According to the present invention, it is possible to stably provide a hot-rolled
steel sheet for a non-oriented electrical steel sheet and a non-oriented electrical steel
sheet which reduce a scale residue during pickling and make the surface qualities of
product sheets favorable at low costs.
[Brief Description of the Drawings]
[0012]
FIG. 1 is an example of a Cu concentration chart in a surface layer of a hotrolled
steel sheet according to the present embodiment.
[Embodiments of the Invention]
[0013]
Regarding a cause for a poor efficiency of scale removal in pickling and the
formation of a scale residue in products, which makes the surface quality poor, in nonoriented
electrical steel sheets that has undergone self-annealing in hot rolling, but
- 5 -
skipped hot-rolled sheet annealing, the present inventors paid attention to surface layer
scale of hot-rolled steel sheets after self-annealing and carried out investigation. As a
result, it was clarified that scale on the surface layer was extremely thick in a hot-rolled
steel sheet self-annealed in hot rolling compared with a hot-rolled steel sheet that had
been threaded through hot-rolled sheet annealing. This is because hot-rolled sheet
annealing was carried out in an atmosphere-controlled furnace while the self-annealing
in the hot rolling was carried out in the atmosphere so that the oxidation of the hotrolled
steel sheet is progressed due to oxygen in the atmosphere.
[0014]
The present inventors intensively studied a method for suppressing the progress
of oxidation in such atmospheric annealing. The idea will be described below.
[0015]
Hot rolling includes slab heating, hot rolling (rough rolling and finish rolling),
and coiling. First, in a slab heating stage, the surface of a slab is oxidized, and scale is
formed. However, the scale in this slab heating stage is removed in the middle of hot
rolling and does not remain on a hot-rolled steel sheet. Scale remaining on the hotrolled
steel sheet is scale that is formed during finish rolling to coiling and after coiling.
[0016]
The formation of the scale is an unavoidable problem as long as the effect of
self-annealing is taken advantage of. Although a steel sheet temperature of a
predetermined value or higher is required for grain growth, it is not possible to control
the atmosphere during hot rolling. Therefore, an attempt was made to make the
chemical composition of the outermost surface of the hot-rolled steel sheet after the end
of the finish rolling of hot rolling oxidation-resistant.
[0017]
- 6 -
As a result, it was clarified that, when Cu was appropriately contained in steel
and Cu was concentrated immediate! y below surface layer scale in the slab heating
stage of the hot rolling, a Cu-concentrated region was exposed on the outermost surface
of the hot-rolled steel sheet after finish rolling. The present inventors found that, when
the Cu-concentrated region is exposed on the outermost surface of the hot-rolled steel
sheet, it is possible to suppress oxidation during self-annealing using the oxidation
resistance of Cu.
[0018]
Furthermore, in pickling following self-annealing, a pickling accelerator
mainly containing thiosulfate is added to a pickling solution, thereby it is possible to
accelerate the removal of an oxide layer formed by the self-annealing. In addition, the
present inventors found that, according to this, it is also possible to avoid the influence
on other kinds of steel that are threaded through the same pickling line using the
easiness of thiosulfate being decomposed in the pickling solution.
[0019]
Based on the above-described findings, the present inventors found conditions
under which the surface quality of products becomes favorable for hot-rolled steel sheet
for a non-oriented electrical steel sheet and non-oriented electrical steel sheets that are
self-annealed during hot rolling and completed the present invention.
[0020]
Subsequently, numerical value-limiting reasons for the components and
products of the hot-rolled steel sheet for a non-oriented electrical steel sheet and the
non-oriented electrical steel sheet according to the present embodiment will be
described. Unless particularly otherwise described, the description of a chemical
composition to be described below is applied to both the hot-rolled steel sheet and the
- 7 -
non-oriented electrical steel sheet according to the present embodiment. Unless
particularly otherwise described, the unit"%" for the amount of each element in the
chemical composition means "mass%".
[0021]

Hereinafter, the components of the hot-rolled steel sheet and the non-oriented
electrical steel sheet will be described.
[0022]
C degrades the iron loss of the non-oriented electrical steel sheet by magnetic
ag1ng. Therefore, the C content is 0.0050% or less. The lower limit of the C content
is 0%. On the other hand, from the viewpoint of avoiding the formation of a solid
solution of B, the C content may be set to 0.0010% or more. The C content may be set
to 0.0045% or less, 0.0040% or less, or 0.0035% or less. The C content may be set to
0.0015% or more, 0.0020% or more, or 0.0025% or more.
[0023]
Si is an element effective for increasing the electric resistance of the nonoriented
electrical steel sheet, and the Si content can be appropriately adjusted
according to required characteristics such as the iron loss, the magnetic flux density, and
the strength. However, when the Si content is less than 0.5%, an iron loss reduction
effect is small. On the other hand, when the Si content exceeds 3.5%, the toughness of
the hot-rolled steel sheet and the non-oriented electrical steel sheet becomes low, which
makes the manufacturing difficult. Therefore, the values described above were
regarded as the upper and lower limits of the Si content, respectively. The Si content
may be set to 3.2% or less, 3.0% or less, or 2.5% or less. The Si content may be set to
0.6% or more, 0.8% or more, or 1.0% or more.
- 8 -
[0024]
Mn acts as a sulfide-forming element and accelerates grain growth in the nonoriented
electrical steel sheet. For the purpose of obtaining this effect, the lower limit
of the Mn content was set to 0.1 %. Furthermore, in order to increase the electric
resistance, the Mn content is preferably set to an appropriate amount according to the
purpose of adjusting the transformation temperature. The upper limit of the Mn
content was set to 1.5% at which these effects were saturated. The Mn content may be
set to 1.2% or less, 1.0% or less, or 0.8% or less. The Mn content may be set to 0.2%
or more, 0.4% or more, or 0.6% or more.
[0025]
Al is an element necessary for the deoxidation of steel. The Al content was
set to 0.1% or more from the viewpoint of ensuring a stable deoxidation effect and
suppressing the formation of fine AlN. Furthermore, an appropriate amount of Al may
be contained in order to increase the electric resistance. On the other hand, excess Al
degrades the castability in steelmaking. Therefore, the upper limit of the Al content
was set to 1.5%. The Al content may be set to 1.2% or less, 1.0% or less, or 0.8% or
less. The Al content may be set to 0.2% or more, 0.4% or more, or 0.6% or more.
[0026]
Cu is an important element in the hot-rolled steel sheet and the non-oriented
electrical steel sheet according to the present embodiment. When an appropriate
amount of Cu is contained in slab, the characteristic of Cu that is less likely to be
oxidized than iron or silicon is taken advantage of and Cu is concentrated in the surface
layer of the hot-rolled steel sheet, so that scale formation is suppressed. In order to
obtain the above-described effects, the Cu content was set to 0.01% or more. Cu may
be more preferably set to 0.010% or more, 0.02% or more, 0.020% or more, 0.05% or
- 9 -
more, or 0.050% or more. However, when the Cu content exceeds 0.10%, a scab
defect is likely to be initiated. Therefore, the upper limit of the Cu content was set to
0.10%. The Cu content may be set to 0.100% or less, 0.08% or less, 0.080% or less,
0.07% or less, 0.070% or less, 0.06% or less, or 0.060% or less.
[0027]
Sn is an important element in the hot-rolled steel sheet and the non-oriented
electrical steel sheet according to the present embodiment. When the characteristic of
Sn that is less likely to be oxidized than iron or silicon is taken advantage of and an
appropriate amount of Sn is contained in the slab, it is possible to suppress scale
formation during hot rolling. In order to obtain the above-described effects, the Sn
content was set to 0.01% or more. The Sn content may be more preferably set to
0.010% or more, 0.02% or more, 0.020% or more, 0.05% or more, or 0.050% or more.
However, when the Sn content exceeds 0.20%, the effects are saturated. Therefore, the
upper limit of the Sn content was set to 0.20%. The Sn content may be set to 0.200%
or less, 0.15% or less, 0.150% or less, 0.10% or less, 0.100% or less, 0.08% or less, or
0.080% or less.
[0028]
The remainder of the chemical composition of the hot-rolled steel sheet and the
non-oriented electrical steel sheet according to the present embodiment is Fe and
impurities. The impurities mean a small amount of elements that are permitted to an
extent that the hot-rolled steel sheet and the non-oriented electrical steel sheet according
to the present embodiment are not adversely affected.
[0029]

- 10 -
In the hot-rolled steel sheet for a non-oriented electrical steel sheet according to
the present embodiment, a Cu-concentrated layer in the surface layer is specified.
First, the Cu concentration needs to have a peak between the surface of the hot-rolled
steel sheet and a depth of 10 ~m. Furthermore, when the Cu concentration peak value
is less than 0.12%, the oxidation of the hot-rolled steel sheet progresses, and a favorable
surface quality cannot be obtained as a product sheet. Therefore, the hot-rolled steel
sheet according to the present embodiment is assumed to have a Cu concentration peak
value of 0.12% or more in a range from the surface to a depth of 10 ~m. The Cu
concentration peak value in the range from the surface of the hot-rolled steel sheet to the
depth of 10 ~m may be 0.13% or more, 0.14% or more, 0.15% or more, or 0.20% or
more. The upper limit value of the Cu concentration peak value in the range from the
surface of the hot-rolled steel sheet to the depth of 10 ~m is not particularly limited,
and, for example, the Cu concentration peak value may be set to 1.00% or less, 0.90%
or less, 0.70% or less, or 0.65% or less.
[0030]

In the non-oriented electrical steel sheet according to the present embodiment
as well, similar to the hot-rolled steel sheet, a Cu-concentrated layer in the surface layer
is specified. Here, the non-oriented electrical steel sheet is obtained by cold-rolling the
hot-rolled steel sheet. In the non-oriented electrical steel sheet obtained by coldrolling
a hot-rolled steel sheet in which the above-described Cu peak position is within
the preferable range, it is normal for the Cu concentration to have a peak between the
surface to a depth of 5 ~m. Therefore, the non -oriented electrical steel sheet according
to the present embodiment is assumed to have a Cu concentration peak value of0.12%
or more in a range from the surface to a depth of 5 ~m. When the Cu concentration
- 11 -
peak value is less than 0.12%, oxidation progresses in the hot-rolled steel sheet stage,
and a favorable surface quality cannot be obtained as a product sheet. The Cu
concentration peak value in the range from the surface of the non-oriented electrical
steel sheet to the depth of 5 ~m may be 0.13% or more, 0.14% or more, 0.15% or more,
or 0.20% or more. The upper limit value of the Cu concentration peak value in the
range from the surface of the non-oriented electrical steel sheet to the depth of 5 ~m is
not particularly limited, and, for example, the Cu concentration peak value may be set to
1.00% or less, 0.90% or less, 0.70% or less, or 0.65% or less.
[0031]
In both the hot-rolled steel sheet and the non -oriented electrical steel sheet, the
Cu concentration peak values are specified using a glow discharge spectrometer (GDS).
Specific methods are as described below.
Pretreatment: The surface of the hot-rolled steel sheet or the non-oriented
electrical steel sheet is cleaned. In a case where the non-oriented electrical steel sheet
has an insulating film, the insulating film is removed, and then the surface is cleaned.
Furthermore, several nanometers of the surface layer of the hot-rolled steel sheet or the
non-oriented electrical steel sheet is removed by argon sputtering.
Measurement: The distribution of the Cu concentration in the depth direction is
measured using the GDS. As a result, a Cu concentration chart as exemplified in FIG.
1 is obtained. Based on the position and height of a Cu concentration peak shown in
this concentration chart, whether or not the Cu concentration peak is included in a
predetermined position and whether or not the concentration is within a predetermined
range are determined.
[0032]

- 12 -
Next, a manufacturing method of the hot-rolled steel sheet for a non-oriented
electrical steel sheet and the non-oriented electrical steel sheet according to the present
embodiment will be described.
[0033]
The manufacturing method of the hot-rolled steel sheet according to the present
embodiment includes steelmaking and hot rolling, the hot rolling includes slab heating,
rough rolling, finish rolling, and coiling, the air ratio in the slab heating of the hot
rolling is set to 1.0 or more and 1.2 or less, the temperature of a rough-rolled steel sheet
immediately before the finish rolling of the hot rolling (a steel sheet obtained by roughrolling
a slab) is set to 1 ooooc or higher and 1 050°C or lower, the finish temperature in
the finish rolling of the hot rolling is set to 930°C or higher and 970°C or lower, and the
coiling temperature in the coiling of the hot rolling is set to 7 50°C or higher and 800°C
or lower. Hereinafter, the reasons for limiting the manufacturing conditions in the
manufacturing method according to the present embodiment will be described.
[0034]
The steelmaking is not particular! y limited. Here, the components of the slab
need to be appropriately adjusted by a well-known method such that the chemical
compositions of the hot-rolled steel sheet and the non-oriented electrical steel sheet are
within the above-described range.
[0035]
In the hot rolling, after the slab is heated, rough rolling and finish rolling are
carried out on the slab to obtain a hot-rolled steel sheet, and furthermore, this hot-rolled
steel sheet is coiled.
[0036]
In the manufacturing method according to the present embodiment, it is
- 13 -
necessary to concentrate Cu immediately below scale by sufficiently forming the scale
on the slab in the slab heating stage. In such a case, it is possible to expose a sufficient
Cu-concentrated layer on the surface of the steel sheet by a descaling treatment before
the finish rolling. In order for that, the air ratio in the slab heating is set within a range
of 1.0 to 1.2. In a case where the air ratio is less than 1.0, there are cases where Cu
concentration does not sufficiently progress and the Cu-concentrated layer cannot be
obtained. In a case where the air ratio is more than 1.2, the amount of the scale
becomes extremely large, the scale cannot be sufficiently removed by a variety of
descaling methods, and the surface properties of the hot-rolled steel sheet or the nonoriented
electrical steel sheet deteriorate.
[0037]
Furthermore, the temperature of a rough-rolled steel sheet before the
subsequent finish rolling is set to 1 ooooc or higher and 1 050°C or lower, and the finish
rolling temperature is set to 930°C or higher and 970°C or lower. This makes it
possible to further concentrate Cu.
[0038]
In addition, the coiling temperature is set to 750°C or higher, whereby the hotrolled
steel sheet is made to be self-annealed, which makes it possible to accelerate
grain growth. In addition, the coiling temperature is set to 800°C or lower, whereby
the internal oxidation of the hot-rolled steel sheet can be suppressed.
[0039]
The manufacturing method of the non-oriented electrical steel sheet according
to the present embodiment includes: manufacturing the hot-rolled steel sheet according
to the present embodiment (that is, the above-described manufacturing method of the
hot-rolled steel sheet according to the present embodiment); pickling; cold rolling; and
- 14 -
final annealing. The cold rolling and the final annealing are not particularly limited,
and well-known conditions can be appropriately adopted.
[0040]
The pickling is also not particular! y limited. Here, a pickling accelerator is
preferably added to a pickling solution for the purpose of further accelerating the
removal of an internal oxidation layer (scale) formed during the self-annealing. There
are cases where the pickling solution remains in the manufacturing stage, which creates
a concern that an adverse effect is caused at the time of manufacturing other kinds of
steel. As a pickling accelerator that does not adversely affect other kinds of steel in
which no internal oxidation layer is present, a thiosulfate-based pickling accelerator is
exemplified.
[Examples]
[0041]
(A) Hot-rolled steel sheets
Slabs having a chemical composition shown in Table 1 were hot-rolled under
slab heating conditions and finish rolling conditions shown in Table 2, thereby obtaining
hot-rolled steel sheets shown in Table 3. In these tables, values outside the scope of
the invention are underlined. These hot-rolled steel sheets were evaluated by the
following methods.
( 1) Measurement of Cu concentration peak values
Pretreatment: The surfaces of the hot-rolled steel sheets were cleaned.
Furthermore, several nanometers of the surface layers of the hot-rolled steel sheets were
removed by argon sputtering.
Measurement: The distributions of the Cu concentrations in the depth direction
were measured using a GDS to obtain Cu concentration charts. Based on the positions
- 15 -
and heights of Cu concentration peaks shown in these concentration charts, whether or
not the Cu concentration peak was included in a predetermined position and whether or
not the concentration was within a predetermined range were determined. Table 3
shows the heights of the Cu concentration peaks (Cu concentration peak values).
(2) Evaluation of scale residue during pickling (evaluation of scale after
pickling)
The hot-rolled steel sheets were immersed in a 6% hydrochloric acid solution
for 60 seconds, then, cross sections were mirror-polished, and the thicknesses of internal
oxidation layers (that is, the thicknesses of scale) were measured with an optical
microscope. Steel sheets having a scale thickness of 1 ~m or less, which was obtained
by the measurement, were determined as hot-rolled steel sheets having favorable scale
evaluation. The thicknesses of the scale may be measured using a scanning electron
microscope.
[0042]

CLAIMS
1. A hot-rolled steel sheet for a non-oriented electrical steel sheet comprising,
by mass%:
C: 0.0050% or less;
Si: 0.5% or more and 3.5% or less;
Mn: 0.1% or more and 1.5% or less;
Al: 0.1% or more and 1.5% or less;
Cu: 0.0 l% or more and 0.10% or less;
Sn: 0.01% or more and 0.20% or less; and
a remainder including Fe and impurities,
wherein the hot-rolled steel sheet has a Cu concentration peak value of 0.12%
or more in a range from a surface thereof to a depth of 10 ~m.
2. A non-oriented electrical steel sheet comprising, by mass%:
C: 0.0050% or less;
Si: 0.5% or more and 3.5% or less;
Mn: 0.1% or more and 1.5% or less;
Al: 0.1% or more and 1.5% or less;
Cu: 0.0 l% or more and 0.10% or less;
Sn: 0.01% or more and 0.20% or less; and
a remainder including Fe and impurities,
wherein the non-oriented electrical steel sheet has a Cu concentration peak
value of 0.12% or more in a range from a surface thereof to a depth of 5 ~m.
3. A manufacturing method of the hot-rolled steel sheet for a non-oriented
electrical steel sheet according to claim 1, the method comprising:
steelmaking; and
- 24 -
hot rolling,
wherein the hot rolling includes slab heating, rough rolling, finish rolling, and
coiling,
an air ratio in the slab heating of the hot rolling is set to 1.0 or more and 1.2 or
less,
a temperature of a rough-rolled steel sheet immediately before the finish rolling
of the hot rolling is set to 1 ooooc or higher and 1 050°C or lower,
a finish rolling temperature in the finish rolling of the hot rolling is set to
930°C or higher and 970°C or lower, and
a coiling temperature in the coiling of the hot rolling is set to 750°C or higher
and 800°C or lower.
4. A manufacturing method of the non-oriented electrical steel sheet
according to claim 2, the method comprising:
pickling;
cold rolling; and
final annealing,
wherein, in the cold rolling, the hot-rolled steel sheet for a non-oriented
electrical steel sheet according to claim 1 is cold-rolled.
5. The manufacturing method of the non-oriented electrical steel sheet
according to claim 4,
wherein a pickling solution used in the pickling contains thiosulfate.